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NETPLUGD(8) BSD System Manager's Manual NETPLUGD(8)
NAME
netplugd - network cable hotplug management daemon
SYNOPSIS
netplugd [-FP] [-c config_file] [-i interface_pattern] [-p pid_file]
DESCRIPTION
netplugd is a daemon that responds to network link events from the Linux
kernel, such as a network interface losing or acquiring a carrier sig-
nal.
When an Ethernet-style network interface on a host is plugged into a
powered-up switch, hub, or other host, the two use a carrier signal to
establish that the link is alive. The Linux kernel makes this informa-
tion available through its netlink(7) interface.
The netplugd daemon listens for carrier detection and loss messages from
the kernel's netlink(7) subsystem. When a carrier signal is detected on
an interface, it runs a script to bring the interface up. When carrier
is lost, netplugd runs a script to bring the interface down. netplugd
does not define any policies for how to manage interfaces; it leaves
that to a script, /etc/netplug.d/netplug, which is described in FILES
below.
You tell netplugd which interfaces it should manage by giving it a list
of shell-style glob patterns, which it matches against using the
fnmatch(3) function. For example, a pattern of eth[13] will tell
netplugd to only manage eth1 and eth3, if those interfaces exist. If
the interfaces are not known to the kernel at the time you start
netplugd, perhaps because they are unplugged PCMCIA network interfaces
or devices whose drivers have not yet been installed, netplugd will
start to manage them as soon as they are plugged in or their drivers are
available.
OPTIONS
-F Run in the foreground; do not detach and run as a daemon. Mes-
sages are logged to stdout or stderr, instead of using the
syslog(3) mechanism. This option is useful mainly for debugging
your configuration.
-P Prevent autoprobing for interfaces. The netplugd daemon nor-
mally probes for all possible interface names that might match
the patterns you tell it to manage. This is necessary in order
to get network driver modules (the default with almost all Linux
distributions) loaded and set up, so that they can provide link
status notifications to the netplugd daemon. Autoprobing should
always be safe, and doesn't take long. Disable it with caution.
-c config_file
Specify the name of a file from which to read patterns that
describe the interfaces to manage. The config file format is
one pattern per line, with white space, empty lines, and com-
ments starting with a # character ignored. You can provide this
option multiple times to read from more than one file. If you
do not provide this option at all, netplugd will attempt to read
from a default config file. If you do not want netplugd to try
to read from any real config files, you can specify /dev/null as
a config file.
-i interface_pattern
Specify a pattern that will be used to match interface names
that netplugd should manage. You can provide this option multi-
ple times to specify multiple patterns.
-p pid_file
Write the daemon's process ID to the file pid_file. If you tell
netplugd to run in the foreground, this option is ignored.
FILES
/etc/netplug/netplugd.conf
Default config file to read, if none is specified on the command
line.
/etc/netplug.d/netplug
The "policy" program (typically a shell script) that netplugd
uses to probe for interfaces, and to bring them up or down in
response to network link events. This program is called with
the name of the interface as its first argument, and one of the
following options:
in A cable was plugged in, or carrier came up. The command
should bring the interface up. The command is run asyn-
chronously, and it should exit with status 0 on success.
out A cable was plugged out, or carrier went down. The com-
mand should bring the interface down. The command is
run asynchronously, and it should exit with status 0 on
success.
probe The command should load and initialise the driver for
this interface, if possible, and bring the interface
into the "up" state, so that it can generate netlink(7)
events. The command is run synchronously; it must exit
with status code 0 if it succeeds, otherwise with a non-
zero exit code or signal.
/etc/rc.d/init.d/netplugd
The init(8) script that starts, stops, and displays status of
the netplugd daemon.
AUTHOR
netplugd was written by Bryan O'Sullivan .
COPYRIGHT AND LICENSE
Copyright 2003 PathScale, Inc. Copyright 2003, 2004 Bryan O'Sullivan
netplugd is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License, version 2, as pub-
lished by the Free Software Foundation. You are forbidden from redis-
tributing or modifying it under the terms of any other license, includ-
ing other versions of the GNU General Public License.
netplugd is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
SEE ALSO
cardmgr(5), hotplug(8), ip(8), netlink(7)
Linux 2.6 August 26, 2003 Linux 2.6
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